diff --git a/FreeRTOS/Demo/Posix_GCC/CMakeLists.txt b/FreeRTOS/Demo/Posix_GCC/CMakeLists.txt
index 199de7508b..6131634b6c 100644
--- a/FreeRTOS/Demo/Posix_GCC/CMakeLists.txt
+++ b/FreeRTOS/Demo/Posix_GCC/CMakeLists.txt
@@ -4,6 +4,8 @@ project( posix_demo )
 
 add_compile_options( -D_WINDOWS_ )
 
+add_compile_options( -Wall -Wextra -Wpedantic )
+
 if( TRACE_ON_ENTER )
     add_compile_options( -DTRACE_ON_ENTER=1 )
 else()
@@ -33,6 +35,9 @@ else()
     set( CMAKE_BUILD_TYPE "debug" )
 endif()
 
+set(CMAKE_CXX_FLAGS_RELEASE "-O3")
+set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g3")
+
 if( SANITIZE_ADDRESS )
     add_compile_options( -fsanitize=address -fsanitize=alignment )
 endif()
diff --git a/FreeRTOS/Demo/Posix_GCC/main.c b/FreeRTOS/Demo/Posix_GCC/main.c
index bf69bf280c..f5773de512 100644
--- a/FreeRTOS/Demo/Posix_GCC/main.c
+++ b/FreeRTOS/Demo/Posix_GCC/main.c
@@ -455,7 +455,7 @@ void handle_sigint( int signal )
         printf( "chdir into %s error is %d\n", BUILD, errno );
     }
 
-    exit( 2 );
+    _exit( 2 );
 }
 
 /*-----------------------------------------------------------*/